Good afternoon,
Thanks for getting in touch. As this is a touring holiday and you pass through several states, due to the size of the USA, temperatures can vary greatly so it's hard to pin down an average for October. The best thing to do is visit some climate websites that track yearly averages, I have found this page to be highly useful over the years,
www.weatherbase.com/weather/state.php3?c=US&refer=&name=United-States-of-America
When you receive your final information via the post, this will contain further information on clothing and climate, I'm sure past travellers will also offer advice, I know there lot's of threads on this forum discussing weather and temperatures etc. For example -
http://www.justyou.co.uk/forum/thread-43992-page-3.html?highlight=Temperature
I hope this helps,
Kindest,
Ben